Bacteria: The Evil of All Root

by Steven Cohen, DDS, Cert. Endo, Gary Glassman, DDS, FRCD(C)

Picture this: A small town in the Wild West Frontier. The street is deserted, it’s high noon, and the sun is beating down on this dust bowl of a town. Two gunfighters square off for a showdown, each at one end of the main street. At one end is the lawman, wearing the white hat, defending all that is good and honourable for the people. At the other end is the villain, wearing the black hat, who feeds on the weaknesses, and fears of these same people. Hanging in the balance is the moral health of this small outpost of civilization.

This struggle is classic to our species. It can be played over and over in almost every facet of human life. We enjoy a greater quality of life because of the advances we have made in biologic research, in technology, and in understanding our bodies and the processes of disease and aging. The status of our oral health is not any different.

At one end of the street, wearing the white hat is the dentist. Traditionally, he/she was armed with a handpiece, a toothbrush, some floss, some fluoride and a pair of forceps. Over time, the handpiece artillery expanded to include higher speed turbines, sonics, ultrasonics, and even lasers. Restorative materials evolved to better adapt and bond. Joining the chemical warfare front with fluoride are sodium hypochlorite, EDTA, calcium hydroxide, chlorhexidine, citric acid, mineral trioxide aggregate, and many other agents. The single solitary dentist has become a team leader, delegating specific battlegrounds to different specialists, each with a specific niche. Replacing the pulps of teeth is one battleground. Regenerating and /or grafting the periodontal support structures are another. Replacing the battle-fatigued tooth (soldier) with an implant is yet another.

At the other end of the street, wearing black, is the bacteria. Primitive, and very, very small, this adversary has been around since the beginning of time. What it lacks in size, it makes up for in huge numbers. It defines the term “opportunistic”. The bacteria also have an armoury of weapons, but these weapons are not quite as tangible. First, there is the huge number of them and their ability to reproduce rapidly. Then there is resistance that develops and evolves and challenges all the dentist’s chemical antimicrobials. Mother Nature then throws in the wild card of genetic mutation, and new strains and species develop. And if, just for an instant, the dentist appears to be gaining a foothold in this battle; there is the one advantage that bacteria have always made the most opportunity out of. That is the weakness of being human… the human body, a variable immune system, and at times a non-compliant healing response.

Decay can and will happen. Probing depths can get deeper. Gingival tissue will recede. Pulps can get inflamed and turn necrotic. Crown margins will leak after a certain amount of time. Root canal treatments can fail. When asked how long a root canal treatment will last, probably the most correct answer is: “as long as the coronal restoration of that tooth stays sound”. Coronal microleakage and recurrent contamination is the most common cause for root canal failure.

If a patient could not master oral hygiene when there were teeth present, what would change when an implant is placed? The added challenge with implants is that there is an entire issue of the health of the host and the health of the recipient site that has to be contended with. It doesn’t matter to the bacteria. They are opportunistic! They will go where the microscopic space allows them, and set up shop. It doesn’t seem to matter to the bacteria whether the pocket they are thriving in is the gingival-root cementum interface, or the gingival-titanium interface.

To some degree, we are too critical of ourselves. When we discuss procedures and materials and quote a “success rate”, we must not forget that the other side of that coin is “failure rate”. Of course there are failure rates. We are human beings treating other human beings.

Throughout any battle, time should be taken to stop and appreciate the victories and the gains that have been made. The “weapons” we use now to complete basic and complex dentistry are fantastic. Our arsenal has expanded tremendously, and the quality of oral health in our country is ranked one of, if not the highest in the world. We should just be wary of that same old enemy. The villain in the black hat is still waiting at the edge of town…and the clock seems to be stuck at five minutes before noon.

Dr. Steven Cohen is an endodontist on staff at Sunnybrook Hospital Dental Clinic and clinical instructor in the graduate programme of Endodontics at the University of Toronto. He maintains a private practice limited to endodontics in Mississauga, ON, Canada.

Dr. Gary Glassman is a fellow and examiner for the Royal College of Dentists of Canada, is the endodontic contributing consultant for Oral Health Journal and maintains a private practice limited to endodontics in Toronto, ON, Canada.